Drain opening compositions in both the solid and liquid form are well known in the art. The solid forms are almost universally based upon strong caustics that generate heat upon addition to water in order to liquify fats and greases and to dissolve hair and soap curd most usually responsible for plugging up the drain. In addition the strong caustic attacks mold slime, food particles and the like to further aid in opening the drain.
The liquid forms are based upon either strong caustics or strong acids and also contain strong oxidizing agents. However these liquid compositions upon addition to water are not capable of generating enough heat to liquify fats and greases as they have little or no heat of solution remaining due to the diluted form in which they are marketed. Consumer safety regulations prevent increase in solution concentrations.
Although such prior art compositions have the ability to remove or dissolve many drain constrictions, a major problem with all such opener compositions is achieving physical and chemical contact between the constriction itself and the drain opener composition. For if actual contact cannot be achieved, the clearing action of the composition is greatly diluted or weakened, and the desired results, i.e., removal of the constrictions, are not achieved.
In this regard, both the physical layout of the drain trap and the type of drain opener are principally to blame. All such traps are in the shape of a U wherein one of the arms is bent over at right angles on the downstream side thus: . If a constriction occurs on the side of the upright arm, that is, the side open to the sink, tub, etc., there is little difficulty in achieving actual contact between the constriction and the opener composition. Similarly, it is frequently easy to achieve contact where the constriction occurs at the bottom of the U, since the opener composition (being heavier than water) will naturally gravitate to the lowest position in the drain. However, in such instances, the use of solid drain openers results in high localized concentrations of caustic which tend to salt out the saponified fatty acids thereby reforming flow barriers and thus the constriction continues. Further, liquid opener compositions are diluted by the water present so as to decrease their immediate effectiveness.
The greater difficulties result when the constriction occurs beyond the bottom of the U, i.e., at some point in the bent arm, and especially immediately before, at, or beyond (downstream) the right angled bend. Physical or chemical contact with such constrictions is especially difficult to achieve since the prior art formulations are heavier than water and therefore tend to remain at the bottom of the U and further are incapable of displacing or mixing with the water trapped between the drain opener composition and the blockage to any appreciable extent.
In order to overcome this difficulty, compositions have been devised which attempt to achieve mixing with the water trapped within the drain. Typically, formulations have been devised that release a gas upon contact with water in the hope that the gas bubbles will force mixing of the drain opener composition with the trapped water. The most well known of solid drain opener compositions contains a strong caustic and aluminum particles, which, in the presence of water, releases hydrogen gas. Studies have indicated that these commercially available compositions are generally quite feeble in achieving a thorough mixing of the opener composition with the water trapped in the drain, especially where the constrictions are in the bent arm portion. These compositions are also known to form an insoluble "caustic heel" in the bottom of the U if the aluminum is not included in the composition or if the first attempt to open the drain is unsuccessful and successive applications of an aluminum containing composition are placed therein.